10.
Key Point
✦
Don’t use Resident Set Size (RSS)
✦
✦
✦
Unless you really want to know what’s currently resident.
It can shrink even while the process size grows.
Heap size or Total memory size is a good indicator.

22.
Key Notes
✦
All variable length data storage comes from malloc
✦
✦
Heads and Bodies are allocated from ‘arenas’ managed by perl
✦
✦
malloc has overheads, bucket and fragmentation issues
Arenas have less overhead but are never freed
Memory usage will always be higher than the sum of the sizes.

24.
Memory Proﬁling?
✦
Track memory size over time?
✦
✦
Experiments with Devel::NYTProf
✦
✦
See where memory is allocated and freed?
Turned out to not be very useful
Need to know what is ‘holding’ memory.